#include        <stdio.h>
#include        <stdlib.h>
#include        <unistd.h>
#include        <fcntl.h>

#define BUFFERSIZE      4096
#define COPYMODE        0644

void oops(char *, char *);

int main(int argc, char *argv[])
{
	int in_fd, out_fd, n_chars;
	char buf[BUFFERSIZE];
	if (argc != 3) {
	fprintf(stderr, "usage: %s source destination\n", *argv);
	exit(1);
								}							if ((in_fd = open(argv[1], O_RDONLY)) == -1)
							      oops("Cannot open ", argv[1]);

												if ((out_fd = creat(argv[2], COPYMODE)) == -1)
														oops("Cannot creat", argv[2]);

															while ((n_chars = read(in_fd, buf, BUFFERSIZE)) > 0)
																	if (write(out_fd, buf, n_chars) != n_chars)
																				oops("Write error to ", argv[2]);
																					if (n_chars == -1)
																							oops("Read error from ", argv[1]);


																								if (close(in_fd) == -1 || close(out_fd) == -1)
																										oops("Error closing files", "");
																										}

																										void oops(char *s1, char *s2)
																										{
																											fprintf(stderr, "Error: %s ", s1);
																												perror(s2);
																													exit(1);
																													}

